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A term introduced by the US physiologist Walter Bradford Cannon (1871–1945), and popularized in his book Bodily Changes in Pain, Hunger, Fear and Rage (1929), for the syndrome of physiological responses of an organism confronted with a situation that evokes fear, pain, or anger, such responses being mobilized by the secretion of adrenalin (epinephrine) from the adrenal medulla, preparing the organism to fight or to flee. It includes increased blood pressure, accelerated heart rate, deepened respiration, increased sweating, dilation of the pupils, diversion of blood flow from the digestive tract to the skeletal muscles and cessation of digestive processes, release of sugar from reserves in the liver, and closure of the sphincter of the bladder, leading to retention of urine.